Some human diseases and defects are directly or indirectly caused by genetic abnormalities. Sickle cell anemia, for example, is caused by a change in just one nucleotide out of six billion. Specific genes have been associated with breast cancer, deafness, and blindness. Some illnesses are caused by complex, interacting environmental and genetic factors and cannot be explained by classical inheritance patterns. Genome studies help medical researchers understand the molecular details of these diseases so they can pursue innovative drug treatments and more quickly identify high-risk individuals who could benefit from early medical intervention. And the analyses of the genomes of disease-causing microbes, viruses, and insects, such as the human malaria parasite and its carrier, the Anopheles mosquito, are helping in the development of new prevention and treatment strategies.
Example: Most cystic fibrosis is from one DNA mutation — deletion of just 3 nucleotides — causing buildup of large amounts of mucus in the lungs.
2. Protecting plant life:
Fungi and other plant pathogens cause billions of dollars in damage every year to agricultural crops, plants, and trees. Sequencing their genomes is helping botanists and foresters find effective treatments. Better understanding of plant genetics is also improving crop yields and enhancing the nutritional value of food.
Example: An oak tree damaged by the sudden oak death pathogen Phytophthora ramorum.
3. Harnessing nature’s technology:
Microbes — nature’s simplest and most abundant organisms — can thrive under extreme conditions of heat, cold, pressure, and even radiation. By studying their genomes, scientists hope to find ways to use bacteria and other microorganisms to solve a variety of environmental problems, develop new energy sources, and improve industrial processes. Some microbes can help clean up hazardous waste sites by absorbing, transforming, or breaking down contaminants — a technique called bioremediation. Others can help combat global warming by absorbing, or sequestering, carbon from the atmosphere. And microbes can convert a wide range of organic and inorganic materials into renewable energy.
Example: The bacterium Rhodopseudomonas palustris can degrade complex aromatic hydrocarbons, assimilate carbon, and provide insights into biomass and biofuel production, particularly hydrogen.
4. Human differences and mutations:
The DNA Sequence in every human is 99.9 percent identical to that of every other human. The slight variations in our genomes are called single nucleotide polymorphisms, or SNPs. Scientists estimate that there are about 1.4 million locations on the genome where SNPs occur in humans. It is these small variations that contribute to individual differences. SNPs and other mutations can be caused by copying errors as DNA is reproduced, or triggered by radiation, viruses, or toxic substances in the environment.
Comparing the DNA sequence patterns of humans side-by-side with those of wellstudied “model organisms” such as the fruit fly, mouse, pufferfish, and sea squirt is one of the most powerful strategies for identifying human genes and determining how they’re regulated and what they do. Conserved sequences—DNA patterns that we share with other organisms—are likely to have important functions or they would have disappeared as the organisms evolved.
The analysis of similar segment of DNA is in the genomes of the human, gorilla, pig, rabbit, mouse, rat and chicken and visualizations make it easier for scientists to identify conserved regions of DNA that could be important in regulating gene and protein function.
6. Functional Non Coding Sequence finding:
Along with helping identify genes and their functions, comparative genomics is shedding light on the functions of the noncoding sequences of DNA found within and between the genes. These segments can regulate gene expression, the process involved in determining when and where in the organism a given gene is turned on or off. Understanding the complex orchestration of gene and protein networks is a crucial aspect of contemporary biomedical research.
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